Pen cap



FIG. 1 is a three-dimensional view of a pen cap showing my new design;

FIG. 2 is the front elevational view thereof;

FIG. 3 is the rear elevational view thereof;

FIG. 4 is the left side elevational view thereof

FIG. 5 is the right side elevational view thereof;

FIG. 6 is the top elevational view thereof; and,

FIG. 7 is the bottom elevational view thereof.

The broken lines showing environment are included for information purposes only and form no part of the claimed design. 

The ornamental design for a pen cap, as shown and described. 